Superradiance of Ultracold Cesium Rydberg |65D5/2> → |66P3/2>

We investigate Rydberg |65D(5/2)> -> |66P(3/2)> superradiance in dense ultracold cesium atoms, where the ground atoms are excited to |65D(5/2)> Rydberg states via two-photon excitation in a standard magneto-optical trap. The superradiant spectrum of |65D(5/2)> -> |66P(3/2)> is obtained using the state-selective field ionization technique. We observe its dynamic evolution process by varying the delay time of ionization field t(d). The results show that the evolution process of |65D(5/2)> -> |66P(3/2)> is much shorter than its radiation lifetime at room temperature, which verifies the superradiance effect. The dependence of the superradiance process on Rydberg atoms number N-e and principal quantum number n is investigated. The results show that the superradiance becomes faster with increasing N-e, while it is suppressed for stronger van der Waals (vdW) interactions. Superradiance has potential applications in quantum technologies, and the Rydberg atom is an ideal medium for superradiance. Our system is effective for studying the strong two-body interaction between Rydberg atoms.